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Thank you for the information. I won't be able to find out the Coil Model # for quite some time (we currently live in the Midwest), but will pass it on when I do if you don't mind. I am now trying to find out about the legality of a mismatched condenser/coil in San Diego since that could be a deal-breaker. If not, I really like the idea of acheiving an overall 12.7 SEER (pretty close to 13!).

In trying to educate myself (hard, in my case), it seems that a less efficient evaporator coil (like the 10SEER in our case) used with a higher rated 13SEER condenser provides more humidity removal because it will run for longer periods. Am I understanding that correctly or confused as usual? Humidity is more an issue than heat for us. Will this cause the evaporator coil to ice up in a mild climate like San Diego? Along the same lines, if we get a 3-ton and it should really be a 2-ton if it was calculated rather than seat of the pants, does that hurt or help to have a condenser that is larger than needed? Stupid questions, I know...

Putting a 13 SEER condenser on a 10 SEER coil will lower the 13 SEER actual efficiency, but probably increase the de-humidification as the coil temp. will be lower therefore achieve more de-humidification (larger temp drop). Where will the condenser be sitting for this upper floor? An outdoor deck? If "icing" becomes a problem (probably won't), it can be remediated with a simple "freeze stat" control.

Don't get stuck on the 3 ton part. It sounds like the first company just pulled that number out of their a$$. I would first identify the evaporator coil and find out how many tons it, along with the air handler and ductwork can handle, and then go from there. You will need to try to find a good contractor who will spend the time to properly evaluate your system. A slightly undersized condenser (outdoor unit) is better than an oversized one, and as was mentioned already, ask them to install a "TXV" for the system to work it's best.

Also, there is probably no reason you couldn't use your existing evap coil with the newer R410A refrigerant. As long as they put the correct R410A metering device (TXV) on it, it should be OK. Especially since it is brand new and has never had R22 running through it.

Technically, an evaporator coil is supposed to be rated for the higher pressures of R410A, but in reality, most of the newer R410A evaporators are actually weaker than the older coils of a few years ago. This is due to the manufacturers making the new ones with thinner-walled copper or aluminum to increase the efficiency so they can meet the governments mandates, and to manufacture them as cheap as possible. Also, most new evaporators are now coming from China or Mexico and the quality control just isn't the same as it used to be.

Luck a dummy, I didn't get any information on the furnace and A/C equipment when we were there. I met a tech from the HVAC company that provided a quote and he said it was good news, everything was there and it "won't cost that much" to put in the condenser, so I thought it was a done deal and left it to them (then we received the quote via email yesterday and about barfed). I should have written down everything. All I have is two really bad snapshots of the utility room that show a bit of the furnace and evaporator coil housing. I don't know if this will help:

You can't see much, but the piping is visible wrapped in plastic coming from the ceiling.

Sounds like the lower 10SEER evaporator coil paired with a higher 13SEER condenser might just be a blessing in disguise for a moderate temperature but humid beach area if I'm understanding this correctly.

Using the R410A in the existing evaporator coil would be great if it can work. Once I determine the model of coil (I only know it is a Rheem), I will post it to see what condenser it will handle. I agree that it is starting to sound like the contractor is "sales oriented" if they didn't do a more thorough evaluation to determine the proper equipment other than ask the approximate sq. footage. I will look for someone else.

In case it matters, here is the location on the 2nd Floor deck that is set up for the condenser. The piping is supposed to be behind the rectangular plate, and the electrical is in the upper box:

Please post your findings after talking to the cities building permits and inspections department. I'm wondering if the contractor might be right about needing 410A. Reason being if the original work didn't get completed there would have been no inspection and the permit expired years ago.No inspection equals no record of the work being done. R22 dry shipped condensors can be installed legally as a component but not as a whole new system. If they have to take a permit out as installing a new system then it could get denied on inspection. The city inspectors will be able to tell you for sure one way or the other. Get it in writing if they say OK!

I would bet what is there probably was inspected and passed under the original mechanical or hvac permit when the place was built. If you are worried about it, you could ask your contractor what they would think. They are the ones that know the inspectors and would likely know weather or not it would be an issue. Besides, if the inspector doesn't like the install, it should be up to the installer to make it right so that it passes.

I wouldn't think an inspector would care weather you went with R22 or R410a, as long as it was done correctly.

With that being said, though, all municipalities and installation contracts are different.

Originally Posted by martyinlincoln

Please post your findings after talking to the cities building permits and inspections department. I'm wondering if the contractor might be right about needing 410A. Reason being if the original work didn't get completed there would have been no inspection and the permit expired years ago.No inspection equals no record of the work being done. R22 dry shipped condensors can be installed legally as a component but not as a whole new system. If they have to take a permit out as installing a new system then it could get denied on inspection. The city inspectors will be able to tell you for sure one way or the other. Get it in writing if they say OK!

I'll be happy to pass along what I have found. I called the city inspector's office today, but they are in the field, and I'll try to catch them next week and let you know. Thank you to everyone. You have all been extremely helpful!

Rheem recommends installing a TXV on that coil if you install a dry R22 unit.
I would get another bid- that coil base should be the same footprint as a new RCFL R410a coil. Should only be a few inches taller than that coil. That coil looks awfully tall for a 10 SEER.
I could swap that coil out in no time- I don't see what the big deal is.
Pull permit- you have to deal with CF-1R, CF-4R, CF-6R & a HERS Rater for duct leakage, TXV/charge verification. I don't think you are going to get away w/ a mismatched system (under 13 SEER) in California w/ permit.